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Invention: Landmine arrows

For over 30 years, Barry Fox has trawled the world’s weird and wonderful patent applications each week, digging out the most exciting, intriguing and even terrifying new ideas. His column, Invention, is now available exclusively online. Scroll down for a round-up of previous Invention articles.

Landmine arrows

The modern military is borrowing an idea from Robin Hood to deal with unexploded landmines. Patents filed by US defence contractor Raytheon concede that current landmine clearance is ineffective, especially if mines are in sand or under water.

But the company has developed a shell containing hundreds of steel “arrows” – 155 millimetres long and 15 mm in diameter – that can trigger landmines with a single shot.

Each rod has a flared rear end, like the feathers of an arrow, and hundreds can be packed into a single cylindrical shell. This shell can be lobbed into a mined area and just before impact a charge behind the arrows will fire them downwards. The metal flights will keep the arrows on a straight course so that they pepper the area at high velocity and at regular spaces.

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Tests show that a shell containing hundreds of arrows can wipe out every mine in an area several metres square, even when the mines are buried under sand or under nearly a metre of water. GPS can also be used to guide the shells into overlapping patches in order to safely clear a wide area.

Smart dressing

Having a bandage changed hurts and takes time. But without removing a dressing, there is currently no way to tell if it is doing a good healing job, or has become dry and needs to be swapped.

So researchers at the University of Strathclyde in Glasgow, UK, have come up with a dressing that can tell doctors whether it needs to be changed or can be left in place.

The dressing material has contact points on the outer surface that lead to a network of electrodes buried inside. When a hand-held reader is placed over the dressing it links outer contacts and sends a low voltage via different paths through the dressing.

A reader then displays a 3D map of the dressing’s conductivity. If the map shows uniformly good conduction, it is good for another day. But if there are too many poor conduction paths, caused by dry patches, the dressing needs changing.

Personal remote

Californian company TiVo plans to make life even easier for couch potatoes. The company already sells Personal Video Recorders (PVR), which can record hundreds of hours of TV and learn what programmes a person most likes in order to record future episodes.

Patents filed in the US show that TiVo plans to take personalised television even further. The company is working on a PVR that will recognise one of several individual users, and respond to their personal preferences.

Every member of a family could have a personal radio frequency tag – embedded in clothing or a piece of jewellery, for example – and the PVR’s remote control would recognise the closest tag. It would then send a corresponding ID signal to the recorder which would use the personal preferences it has built up for the tag-wearer only.

TiVo even hopes to extend personalisation to hotels that have in-room PVRs. When booking a room online, a guest could upload the preferences stored on their home recorder. The PVR in their hotel room would then record a few favourite programmes ahead of their arrival.